A number of methods for producing chemically adsorbed films that exhibit excellent resistance to peeling, a high level of transparency, and do not impair the gloss of the substrate surface or the substrate transparency are already known as suitable methods for forming a coating film that improves the properties of a substrate surface (see Japanese Unexamined Patent Application, First Publication No. Hei 4-132637, Japanese Unexamined Patent Application, First Publication No. Hei 4-221630, and Japanese Unexamined Patent Application, First Publication No. Hei 4-367721).
As a method for forming a chemically adsorbed film on a substrate surface that contains active hydrogen, a method is known in which a mixed solution containing at least an alkoxysilane-based surfactant, a non-aqueous solvent with no active hydrogen, and at least one silanol condensation catalyst selected from a group consisting of carboxylic acid metal salts, carboxylate metal salts, carboxylic acid metal salt polymers, carboxylic acid metal salt chelates, titanate esters, and titanate ester chelates is brought into contact with a substrate surface, thereby forming a chemically adsorbed film that is covalently bonded to the substrate surface via siloxane bonds (see Japanese Unexamined Patent Application, First Publication No. Hei 8-337654).
As a method for forming a chemically adsorbed film that exhibits crystallinity on a substrate surface, a method is known in which an organic solvent solution of a silane-based surfactant is developed on the surface of a silicon wafer onto which purified water has been dripped, thereby forming a crystalline monomolecular film (see Bull. Chem. Soc. Jpn., 74, 1397 to 1401 (2001)).
Methods for forming water repellent films are also known in which, by using the monomer or polymer of a hydrolysis product of a fluoroalkyl group-containing silane compound, produced by hydrolysis in the presence of an acid catalyst, a water repellent film formed from a monomolecular layer of the hydrolysis product is fixed to the substrate surface via silanol groups (see Japanese Unexamined Patent Application, First Publication No. Hei 11-228942, Japanese Unexamined Patent Application, First Publication No. Hei 11-322368).
As a method for forming a monomolecular film on a substrate surface that contains active hydrogen, a method for producing a chemically adsorbed monomolecular film is known which includes the steps of coating the surface of a substrate, in a dry atmosphere, with a chemical adsorption solution prepared using a non-aqueous organic solvent and a silane-based surfactant, chemically reacting the surfactant molecules within the adsorption solution with the surface of the substrate while the organic solvent is concentrated by evaporation, thereby bonding and fixing one end of the surfactant molecules to the substrate surface, and then using an organic solvent to wash and remove any unreacted surfactant left on the substrate surface following evaporation of the organic solvent (see Japanese Unexamined Patent Application, First Publication No. Hei 11-147074).
However, a number of problems arise in all of the methods described above, including the lengthy time required to form the film, the fact that residual silanol condensation catalyst remains in the film, inhibiting the chemical adsorption and preventing formation of a dense monomolecular film, the fact that acidic materials are generated, meaning there are restrictions on the type of substrate that can be used, and the fact that film formation must be conducted in a non-aqueous system. The stable provision of dense monomolecular films with minimal impurities is keenly sought, particularly for micropatterning in the design of electronic devices and the like. Furthermore, using the conventional methods described above, no examples are known of the formation of a crystalline chemically adsorbed film on the surface of an amorphous substrate.